Bug #20965: `it` vs `binding.local_variables`

• Status: Closed
• Assignee: -
• Target version: -
• ruby -v: ruby 3.4.0dev (2024-12-15T13:36:38Z master 366fd9642f) +PRISM [x86_64-linux]
• Backport: 3.1: DONTNEED, 3.2: DONTNEED, 3.3: DONTNEED

[zverok (Victor Shepelev)]

it is not available in the list of binding.local_varaibles, unlike numbered parameters:

p(proc { binding.local_variables }.call)  # []
p(proc { |x| binding.local_variables }.call)  # [:x]
p(proc { _1; binding.local_variables }.call)  # [:_1]
p(proc { vars = binding.local_variables; _1; vars }.call)  # [:_1, :vars]
p(proc { it; binding.local_variables }.call)  # []

I wonder if it is deliberate or accidental.

[zverok (Victor Shepelev)]

• ruby -v set to ruby 3.4.0dev (2024-12-15T13:36:38Z master 366fd9642f) +PRISM [x86_64-linux]

[shan (Shannon Skipper)]

It does seem like that last one should be [:it] for consistency if it wasn't intentional. +1

An aside, but it's also interesting that using _2 causes _1 to also be defined under Binding#local_variables.

proc { _9; local_variables }.call
# => [:_1, :_2, :_3, :_4, :_5, :_6, :_7, :_8, :_9]

proc { it; local_variables }.call
# => []

[nobu (Nobuyoshi Nakada)]

https://github.com/ruby/ruby/pull/12398

[k0kubun (Takashi Kokubun)]

• Related to Feature #18980: `it` as a default block parameter added

[nobu (Nobuyoshi Nakada)]

• Status changed from Open to Closed

Applied in changeset git|46fec0f62a1803d44edb8b06e39ac0f358e56670.

---

[Bug #20965] Define it like an ordinary argument (#12398)

Also fixes [Bug #20955]

[tompng (tomoya ishida)]

I have a concern of making it parameter an lvar.

1| 42.tap do
2|   p binding.local_variable_get('it')
3|   it /1/i
4|   p it
5| end

When parser reads p it at line 4, it turns out to be a local variable, I think from the beginning of the block(from line 2).
But on line 3, it /1/i is already parsed as if lvar it does not exist.

It is impossible to re-parse the block again, so the original implementation(it parameter is not an lvar) makes sense to me.